CERTAIN SUGARS CONSIDERED SAFE as sweeteners in the human food supply can double as environmentally-friendly pest remedies, and even make biological control of insects by beneficial fungi more practical for households, farms and gardens. Considering that caffeine from coffee grounds can be used against deadly dengue mosquitoes and that a variety of traditional herbs can blast away bed bugs, insecticidal sugar compounds should come as no surprise. Perhaps the only remedy more surprising is that rain water or simulated rain sprays from hoses or irrigation equipment can safely wash away pests with no toxic pesticide residues to worry about in the environment.

Using sugars directly to slay insects is somewhat unusual. However, sugars are commonly used as attractants, for instance to lure fruit flies, moths or ants to baits and traps both for population control and as a survey method or monitoring tool. California citrus growers have a long history of using sugar sprays as an IPM (integrated pest management) strategy to lure fruit-scarring citrus thrips to organic or botanical formulations of ryania (“from woody stem and root materials of plants of the genus Ryania”) or sabadilla (alkaloids from seeds of a lily bulb, Schoenocaulon officinale). “INTEGRATED PEST MANAGEMENT implies that techniques used to manage one pest species should not disrupt techniques used to manage other pests of the same crop,” wrote J.D. Hare and Joseph Morse in the Journal of Economic Entomology. “In citrus pest management in California, this situation is well illustrated in the choice of pesticides for the management of one major pest, citrus thrips, Scirtothrips citri (Moulton), without disruption of several effective biological control agents of the other major pest, California red scale, Aonidiella aurantii (Maskell).”

That sugars can be lethal to pests and be a source of environmentally-friendly pesticides is not exactly intuitive. “Potential of the non-nutritive sweet alcohol erythritol as a human-safe insecticide” was the strangely intriguing title of Drexel University’s Sean O’Donnell’s presentation at the Entomological Society of America (ESA) annual meeting. Many of the details were previously published in PLoS ONE, an open access journal, and in part because of the origins of the research in a grade school science project by one of the researcher’s sons, aspects of the story have been widely reported in various media. “Erythritol is a zero-calorie sweetener found in fruits and fermented foods,” summarized Lauren Wolf in Chemical & Engineering News, and “is Generally Recognized As Safe by the Food & Drug Administration and has been approved as a food additive around the globe.”

“Many pesticides in current use are synthetic molecules such as organochlorine and organophosphate compounds,” and “suffer drawbacks including high production costs, concern over environmental sustainability, harmful effects on human health, targeting non-intended insect species, and the evolution of resistance among insect populations,” write the researchers in PLoS ONE. “Erythritol, a non-nutritive sugar alcohol, was toxic to the fruit fly Drosophila melanogaster. Ingested erythritol decreased fruit fly longevity in a dose-dependent manner, and erythritol was ingested by flies that had free access to control (sucrose) foods in choice and CAFE (capillary feeding assays) studies…

“We initially compared the effects of adding five different non-nutritive sugar substitutes (Truvia, Equal, Splenda, Sweet’N Low, and PureVia,” wrote the researchers in PLoS ONE. “Adult flies raised on food containing Truvia showed a significant reduction in longevity…We noted that adult flies raised on food containing Truvia displayed aberrant motor control prior to death. We therefore assayed motor reflex behavior through climbing assays…Taken together with our longevity studies, these data suggested some component of the non-nutritive sweetener Truvia was toxic to adult Drosophila melanogster, affecting both motor function and longevity of this insect…

“Our initial analysis of sweeteners included two sweeteners that contained extracts from the stevia plant, Truvia and Purevia. While adult flies raised on food containing Truvia showed a significant decrease in longevity compared to controls, this was not the case for flies raised on Purevia. These data suggest stevia plant extract was not the toxic element in these sweeteners. Purevia contains dextrose as a bulk component, while Truvia contains erythritol as a bulk component…To determine if erythritol was the toxic component of Truvia, we repeated our longevity studies on food containing equal weight/volume (0.0952 g/ml) of nutritive sugar control sucrose, and non-nutritive sweeteners Truvia, Purevia, and erythritol. We assured the flies were successfully eating the foods containing these sweeteners through dye labelling the food with a non-absorbed blue dye (blue food), and visual confirmation of blue food present in fly abdomens and proboscises daily…The average percentage of blue abdomens throughout the study were 97.46%.”

“These data confirm all treatment foods (including Truvia and erythritol treatments) were consumed by adult flies, and suggest mortality was not due to food avoidance and starvation…A large body of literature has shown that erythritol consumption by humans is very well tolerated, and, indeed, large amounts of both erythritol and Truvia are being consumed by humans every day throughout the world. Taken together, our data set the stage for investigating this compound as a novel, effective, and human safe approach for insect pest control. We suggest targeted bait presentations to fruit crop and urban insect pests are particularly promising.”

Interestingly, a few decades ago UK researchers found that the sweeteners (sugar alcohols; polyols) erythritol, glycerol and trehalose rendered more effective several insect biocontrol fungi, Beauveria bassiana, Metarhizium anisopliae and Paecilomyces farinosus. These insect-killing fungi need a relative humidity (RH) near 100% for germination of their conidia (seed-like propagules). “Conidia with higher intracellular concentrations of glycerol and erythritol germinated both more quickly and at lower water activity,” wrote UK researchers J.E. Hallsworth and N. Magan in the journal Microbiology. “This study shows for the first time that manipulating polyol content can extend the range of water availability over which fungal propagules can germinate. Physiological manipulation of conidia may improve biological control of insect pests in the field…Although fungal pathogens have been used to control insect pests for more than 100 years, pest control has been inadequate because high water availability is required for fungal germination.”

Curiously, erythritol and glycerol, besides being sweetening substances, also function as antifreeze compounds. Certain Antarctic midges, known as extremeophiles for living in an ultra-cold habitat, ingest and sequester erythritol from their food plants; and as antifreeze it protects the adult flies from freezing. Indeed, many mysteries remain. Besides being found in green plants like stevia and in lower amounts in fruits, erythritol is found in certain mushrooms, lichens and algae. Human and animal blood and tissues apparently have low endogenous levels of erythritol; and erythritol is a yeast fermentation product (hence in sake, beer, wine). In human medicine, erythritol has been used for coronary vasodilation and treating hypertension; and according to Japanese microbiologists, erythritol ingestion may mean fewer dental cavities (caries) than sucrose sugar.

BED BUGS CAN be spiked and trapped by tiny spears like leaf hairs, and can become dehydrated or dessicated and rendered harmless by certain forms of silicon, the second most abundant element in planet Earth’s crust (28%) after oxygen (47%). That silicon can be the bane of bed bugs is indeed odd when one considers that silicon permeates our world from beach sands, opals, agates and quartz crystals to sandpaper, semiconductors, glasses, ceramics, optical fibers and cosmetic products. Indeed, the famous French scientist and silkworm entomologist, Louis Pasteur, whose name has become synonymous with the germ theory of medicine, predicted silicon’s eventual service in human medicine; though Pasteur was probably not thinking along the lines of silica gels and desiccant diatomaceous earth dusts as remedies for the 21st century’s worldwide medical plague of bed bugs.

Despite its commonness in nature and the human environment and potential uses in human medicine, the use of silicon products comes with caveats to users, who might want to wear sufficient protective clothing and respirators to avoid inhaling the products. Strangely enough, that much maligned metabolic waste product, carbon dioxide, which along with sunlight is essential to photosynthesis and life on planet Earth, is perhaps a safer component (e.g. as a lure or attractant) when integrated into bed bug traps. Food grade diatomaceous earth made from freshwater diatoms is considered relatively nontoxic; whereas filtering grade diatomaceous earth (e.g. the type used for swimming pool filters) is a crystalline form with inhalation toxicity.

“Louis Pasteur (1822-95) said that silicon would prove to be a treatment for many diseases and in the first quarter of the twentieth century there were numerous reports by French and German doctors of sodium silicate being used successfully to treat conditions such as high blood pressure and dermatitis,” wrote British chemist John Emsley in his superb compendium, Nature’s Building Blocks (An A-Z Guide to the Elements). “By 1930, such treatments were seen to have been in vain and the medication fell out of favor. So things rested, until the discovery that silicon might have a role to play in human metabolism, and then followed suggestions that it could have a role in conditions such as arthritis and Alzheimer’s disease, but no new treatment based on these suggestions has yet emerged. Meanwhile, silicon continues to be linked with a disease of its own: silicosis. Miners, stone-cutters, sand-blasters and metal-grinders develop this lung condition which is a recognized occupational disorder caused by the inhalation of minute particles of silica…” Symptoms include coughing, wheezing and shortness of breath; a more aggressive form of silicosis associated with certain types of asbestos can develop into lung cancer and has been a rich source of litigation for occupational exposure in the USA.

While silica products should be used sparingly (a caution that should also apply to most sprays) or not at all by some people (e.g. existing respiratory problems; perhaps seek a medical opinion before using), they might prove for many others the tipping point for winning the bed bug war as part of an integrated approach that controls bed bugs (many of which are pesticide resistant) using a multiple arsenal of weapons including herbal oils, clutter reduction, heat, sealing crack and crevice harborages, traps, pheromones, carbon dioxide, vacuuming under baseboards, etc.

At the 2014 Entomological Society of America (ESA) annual meeting, Kyeong-Yeoll Lee of South Korea’s Kyungpook National University (Daegu) reported that silica in the form of diatomaceous earth (Perma-Guard(TM) or Fossil-Shell(R)) acted as a synergist when heat (hot air) fumigations substituted for chemical fumigants such as methyl bromide. Though the test insect was Indian meal moth, a worldwide pest of stored grain and many other packaged agricultural products, it would not be surprising to find that heat treatments combined with silica products like diatomaceous earth will also prove efficacious and perhaps also synergistic against bed bugs. Indeed, heat treatments may induce bed bugs to move around more, which could hasten contacting diatomaceous earth and water loss.

At the same 2014 ESA meeting, Virginia Tech (Blacksburg, VA) researcher Molly Stedfast provided some impressive results via the time-consuming process of first educating apartment residents about bed bugs and then painstakingly vacuuming along baseboards to suck up as many bed bugs as possible before applying the silica products under the baseboards to further reduce bed bug populations. This integrated (IPM; integrated pest management) approach required quite a bit of manual labor, as furniture had to be moved to gain access to the baseboards before vacuuming and then applying silica gel or dust products.

Stedfast tested two silica products, Mother Earth(TM) D, a highly-absorptive desiccant dust made from 100% freshwater diatomaceous earth, and CimeXa(TM) Insecticide Dust, a 100% amorphous silica gel. The silica dust or gel injures the insect cuticle (outer protective “skin”), letting water leak out and leading to dehydration (providing relative humidity is not extremely high, above 81%; and free water is unavailable). Both the diatomaceous earth and silica gel products were “very effective at killing bed bugs even at 10% of the label rate.” Going above the label rate was a waste of resources, as only so much product can contaminate the bed bugs. Bed bugs can die within 24 hours of contacting the silica products, but air currents that blow the dusts around can be a problem; also the products need to stay moist and not dry out to be effective. Among Stedfast’s biggest headaches is the application equipment, which was not very robust.

The patent literature reveals that inventors such as Roderick William Phillips in Vancouver are working on improved spray apparatuses for applying diatomaceous earth: “There is disclosed a spray apparatus for holding contents comprising diatomaceous earth and a compressed propellant for propelling the diatomaceous earth. There is also disclosed use of diatomaceous earth to control a population of bedbugs…diatomaceous earth, a naturally occurring siliceous sedimentary rock that includes fossilized remains of diatoms. However, known methods of applying diatomaceous earth can be cumbersome. For example, known methods of applying diatomaceous earth may undesirably require handling the diatomaceous earth, for example to transfer the diatomaceous earth from a container not having an applicator to a separate applicator apparatus. Also, known applicator apparatuses may apply diatomaceous earth unevenly, which may be wasteful or ineffective. In general, known methods of applying diatomaceous earth may be sufficiently complex so as to require professional involvement, which may undesirably add to cost and delay of bedbug treatment. Also, numerous types of diatomaceous earth are available, and different types of diatomaceous earth vary widely and significantly from each other. It has been estimated that there are approximately 100,000 extant diatom species…and may vary widely and significantly in size and shape across a very large number of diatom species…”

At the University of British Columbia (Vancouver), Yasmin Akhtar and Murray Isman demonstrated that both diatomaceous earth and herbal or botanical compounds such as neem, ryania and rotenone are to varying degrees transported by adult bed bugs and contaminate other adults and younger bed bug nymphs. “Our data clearly demonstrate horizontal transfer of diatomaceous earth and botanical insecticides in the common bed bug,” said Akhtar and Isman. “Use of a fluorescent dust provided visual confirmation that contaminated bed bugs transfer dust to untreated bed bugs in harborage. This result is important because bedbugs live in hard-to-reach places and interaction between conspecifics can be exploited for delivery and dissemination of management products directed at this public health pest…This result is important because bedbugs live in hard-to-reach places (cracks, crevices, picture frames, books, furniture) and as such interaction between the members of the colony can be exploited for delivery and dissemination of control products.”

At the 2014 ESA annual meeting, Akhtar suggested protecting travelers and suppressing bed bug transit by building diatomaceous earth into luggage, mattresses and fabrics. Diatomaceous earth provided 96% repellence; bed bug mortality was zero at 24 hours, but 93% after 120 hours. Diatomaceous earth could also be applied to box springs, dressers and headboards, and under carpets and inside drywall. A diatomaceous earth aerosol provided 81% bed bug mortality at 30 days, and was still active and being transferred from dead bed bugs to live bed bugs.

Diatom species mined for diatomaceous earth are stunning in their architectural variety and beauty. Ultimately, the silicon secrets of living diatoms has the potential to transform “the manufacture of siloxane-based semiconductors, glasses, ceramics, plastics, elastomers, resins, mesoporous molecular sieves and catalysts, optical fibers and coatings, insulators, moisture shields, photoluminescent polymers, and cosmetics,” wrote UCSB marine scientist Daniel E. Morse. “The manufacture of these materials typically requires high temperatures, high pressures or the use of caustic chemicals. By contrast, the biological production of amorphous silica, the simplest siloxane [(SiO2)n], is accomplished under mild physiological conditions, producing a remarkable diversity of exquisitely structured shells, spines, fibers and granules in many protists, diatoms, sponges, molluscs and higher plants. These biologically produced silicas exhibit a genetically controlled precision of nanoscale architecture that, in many cases, exceeds the capabilities of present-day human engineering. Furthermore, the biological productivity of siloxanes occurs on an enormous scale globally, yielding gigatons per year of silica deposits on the floor of the ocean. Diatomaceous earth (composed of the nanoporous skeletons of diatoms) is mined in great quantities from vast primordial deposits of this biogenic silica.”

HERBAL OILS such as NEEM can reduce bed bug populations when integrated with other pest control technologies such as traps. As desperation hits with more bed bug populations resistant to more conventional synthetic pesticides, more herb and essential oil formulations and fumigations, as well as silicon dioxide-based gels and dusts such as diatomaceous earth, are being integrated with other bed bug remedies such as clutter reduction and heat fumigation.

Those in thrall to chemical industry protocols adhere to the standard that a remedy must kill 95% in laboratory tests. But it is most often a hypocritical standard, as over time bed bugs are almost guaranteed to become genetically selected for resistance to widely used synthetic pesticides. According to Virginia Tech researchers: “A frightening resurgence of bed bug infestations has occurred over the last 10 years in the U.S. and current chemical methods have been inadequate for controlling this pest due to widespread insecticide resistance…While DDT was initially effective for bed bug control, resistance to the cyclodienes was well documented among different bed bug populations by 1958…bed bugs had developed resistance to organophosphate insecticides, including malathion by the 1960s…While there have been many hypotheses regarding the cause of the bed bug resurgence, the cause is at least partially explained by bed bug resistance to insecticides, in this case, those in the pyrethroid class,” including deltamethrin resistance in New York City bed bugs.

To that conclusion, I would add “over-reliance on synthetic chemical pesticides” to the exclusion of designing habitations to be inhospitable to bed bugs and alternative control methods. Oddly enough, herbal remedies not killing 95% are often subject to persecutory calls of marketplace banishment by the EPA, FDA, FTC or one of the myriad other USA.gov regulatory bureaucracies. An Alternative in the Internet age is letting people decide for themselves via Internet search engines before buying. To some extent, government regulation of herbal pest control efficacy is unnecessary when scientific test results can be posted on the Internet and debated.

An integrative approach can make excellent use of herbal remedies providing perhaps 40% or 60% bed bug reduction; in conjunction with heat treatments, sharp silicon dioxide crystals and other remedies that collectively might add another 30%, 40% or 50% bed bug reduction. It’s all mathematics, which many people hate; but nonetheless a 60% bed bug reduction from an herbal remedy combined with a 40% reduction from clutter reduction, heat fumigation or traps can easily equal over 95% control (the laboratory standard adhered to by those one-trick chemical ponies sometimes called “nozzle heads”).

In other words, herbal oils and other alternative treatments can leverage themselves when intelligently combined with other pest control methods such as heat, clutter reduction and traps. That should be intuitive, but it runs counter to the entomology training of the average PhD in the USA. The late “Professor (Robert) van den Bosch of the University of California was one of the developers of Integrated Pest Management” (IPM) and an advocate of biological controls; and he made the case for a multi-faceted approach to cotton and food crop pests long ago in books like The Pesticide Conspiracy (University of California Press).

Bed bugs and the urban environment of hotels, apartments, cracks, crevices, mattresses, trains, buses, backpacks and luggage of course present a different set of problems than a homogeneous field of crops or a laboratory spray arena. But you be the judge of whether herbal fumigations work against bed bugs: At the Entomological Society of America annual meeting, Korean researcher Jun-Ran Kim (Rural Develop Admin, Suwon-si Gyeonggi-do, South Korea) compared 120 herbal or botanical essential oils to the best conventional pesticides for controlling insecticide-susceptible and insecticide-resistant adult bed bugs hiding in protected places (as bed bugs do; e.g. cracks, crevices, inside electrical sockets).

Kim singled out two essential oils, those from peppermint (Mentha piperita) and myrtle (Myrtus communis) plants, as most effective and worth further development as bed bug fumigants. So, should the headline read: “Essential Oils a Failure as Bed Bug Fumigants,” as 118 of 120 essential oils did not make the cut. Indeed, fewer than 2% of the botanical oils tested, peppermint and myrtle, were singled out as potential bed bug fumigants. Or should the headline read: “Essential Oils Effective Bed Bug Fumigants,” or “Peppermint and Myrtle Oils Prove Essential Oils Can Work as Bed Bug Fumigants.”

Rue, an ancient herb, needs to be tested against bed bugs. Natural products researchers report: “An infusion of Ruta chalepensis leaves rubbed onto skin has been purported to be repellent to mosquitoes and other insects by farmers and shepherds in rural and mountainous areas of Marche and Latium, Central Italy. In the same Italian countryside, Ruta graveolens leaves were set under the bed to repel bugs and mice (Guarrera 1999). A decoction of Ruta species also has been used topically against scabies, lice, and fleas, to repel insects and to treat intestinal worms in livestock.”

Intriguingly, rather than following up on rue under the bed to fight bed bugs, Italian researchers veered off in another direction: Rue, as a sustainable weed control alternative for corn field weeds such as purslane and pigweed: “Poisonous plants are neglected sources of natural herbicides. An infusion of such a plant rue (Ruta graveolens L.) was tested…rue infusion (100 g/l) and its isolated allelochemicals…open up a promising avenue in the search of natural herbicides.”

Other researchers envision the disease-fighting properties of herbs such as rue and powders such as sodium bicarbonate (baking soda or bicarbonate of soda) being harnessed as alternatives to synthetic fungicides. Indeed, in organic and sustainable conventional farming, rue “at low rates…may lessen the onset of fungicide resistance” against powdery mildew, brown spot and other plant diseases in diverse crops, including strawberries.

Italian researcher Giovanni Aliottal and colleagues in a paper titled “Historical Examples of Allelopathy and Ethnobotany from the Mediterranean Region,” write: “Ruta graveolens L. (Rutaceae), or common rue, originating in Southern Europe, is an evergreen shrub with bluish-green leaves that emits a powerful odour and has a bitter taste. The plant is cited in the ancient herbals and has deep roots in folklore, alchemy and even demonology. Rue has been regarded from the earliest time as successful in warding off contagion and preventing the attacks of fleas and other noxious insects. The name rue derives from the Greek “reuo” (= to set free), because the plant is efficacious in various diseases. Rue was the chief ingredient of the famous antidote to poison used by Mithridates. It was also known to produce erythema and pustular eruptions on human skin. Many remedies containing rue as well as its abortive properties were mentioned by Pliny the Elder in his Naturalis Historia (XX, 143). In Europe, rue was considered a powerful defense against witches during the Middle Ages. Piperno, a Neapolitan physician, in 1625, recommended rue as a treatment for epilepsy and vertigo. Today, the aerial parts of the plant are eaten in Italian salads, and are said to preserve the eyesight. Rue is currently mentioned in the pharmacopoeias of 28 countries where it is considered mainly as a stimulating, antispasmodic, diuretic and emmenagogue. Moreover, fresh and dried leaves are used to preserve and to flavour beverages and foods such as liquor (grappa) and wine, cheese and meat.”

Ruta graveolens is the scientific name for garden rue or herb-of-grace, one of about 1,500 species in the plant family Rutaceae (includes oranges, lemons, other citrus). A native of the Balkans and southeastern Europe grown worldwide, rue is known as sudab or sadab in India, arvada in Tamil, aruda in Singhalese, gedung minggu in Javanese and geruda in Malay. Ruta chalepensis is the scientific name for fringed rue, Aleppo rue or Egyptian rue. Rue researchers D. H. Tejavathil and B. L. Manjula in India summarize: “Ruta graveolens L., a member of Rutaceae, is well known for its wide utilities such as ornamental, aromatic and culinary in addition to medicinal properties. Medicinal value of this taxon is attributed to the accumulation of flavonoids, furanocoumarins, acridine alkaloids, furanoquinolins and also essential oils which led to its recognition as one of the sought after traditional medicinal plants by pharmaceuticals.” Perhaps a bit dangerous, too; according to Egyptian researchers: “On moist skin in direct sunlight, it leads to photosensitivity. The essential oil is a central nervous system depressant and at high doses has become a narcotic.”

A major rue essential oil component, 2-undecanone, is nicely summarized in wikipedia: “2-Undecanone is used in the perfumery and flavoring industries, but because of its strong odor it is primarily used as an insect repellent or animal repellent. Typically, 1–2% concentrations of 2-undecanone are found in dog and cat repellents…” According to its web site claiming “invention” by Dr. R. Michael Roe and referencing 3 patents: “North Carolina State University is currently seeking an industry partner to commercialize a novel, natural insect repellent for mosquitoes, ticks, chiggers, bedbugs, house dust mites, cockroaches, and other pests…A researcher at North Carolina State University has discovered that undecanone and related structures are repellents of mosquitoes, ticks, bed bugs, cockroaches, thrips, aphids, deer flies, gnats and other animals. In some tests, these compounds were found to be more effective than DEET…”

The Flowers of Chania web site provides a nice overview of rue species used as medicine in Crete, grown in Netherlands botanical gardens, and mentioned in Shakespeare’s Hamlet. Unlike the Balkan bean leaf remedy for spearing bed bugs, which has recently sparked the interest of those desperate for bed bug remedies, medicinal plants in the rue family known since ancient times have escaped scientific scrutiny against bed bugs. Probably much to the delight of bed bugs worldwide. According to researchers in India, “The most frequent intentional use of the plant has been for induction of abortion.” If only that powerful rue activity could be integrated to naturally abort bed bug populations just enough to allow humans a more bite-free sleep.

According to the USA FDA (Food and Drug Administration) web site: ““GRAS” is an acronym for the phrase Generally Recognized As Safe. Under sections 201(s) and 409 of the Federal Food, Drug, and Cosmetic Act (the Act), any substance that is intentionally added to food is a food additive, that is subject to premarket review and approval by FDA, unless the substance is generally recognized, among qualified experts, as having been adequately shown to be safe under the conditions of its intended use, or unless the use of the substance is otherwise excluded from the definition of a food additive. Under sections 201(s) and 409 of the Act, and FDA’s implementing regulations in 21 CFR 170.3 and 21 CFR 170.30, the use of a food substance may be GRAS either through scientific procedures or, for a substance used in food before 1958, through experience based on common use in food.”

In other words, if there is a long tradition of eating the stuff and smearing it on your body, it is likely not to need hundreds of millions of dollars and decades of testing and regulatory agency compliance like a pharmaceutical product. So, you don’t have to wait 15 years for a bed bug remedy that will be several times more costly (to recoup the regulatory expenses) than what is already available. Being publicly sold on the Internet, samples of these GRAS pesticide products can often be obtained free of charge by researchers for scientific studies. Sometimes the studies, even if taxpayer or public funded, are published in respected commercial journals and hidden from public perusal behind formidable paywalls. But Internet search engines can usually at least turn up abstracts, media reports and summaries of varying quality and usefulness.

Rutgers researchers compared 11 herbal and detergent products (e.g. Sodium Lauryl Sulfate) and two synthetic pesticide products against bed bugs. A nice summary by the researchers published in an industry trade publication and titled “Natural Pesticides for Bed Bug Control: DO THEY WORK?” was made freely accessible via the Internet. Bed bugs were placed in laboratory chambers offering no escape from spray contact; a valid approach for most product comparisons. But given that many bed bug populations are pesticide resistant and that in real rooms bed bugs hide and avoid spray contact, real world results are usually lower than the lab numbers. These are more or less truisms, for both botanical and synthetic pesticide products. Which is why pest control operators often are called back to spray multiple times over several months or years; and why you need an integrative approach (relying on more than just sprays) and plenty of patience to rid yourself of bed bug infestations. A quick overview of integrative bed bug alternatives with a resource list is found in the Jan. 2015 issue of the IPM Practitioner (as of this writing, still available for free Internet download).

According to the Rutgers researchers, Temprid SC [Imidacloprid (21%) and Beta-Cyfluthrin (10.5%)] killed 100% of exposed adult bed bugs coming in contact with the spray in three days, and “was significantly more effective than Demand CS” [Lambda-Cyhalothrin (9.8%)]. The best herbal formulations were a bit slower: “EcoRaider and Bed Bug Patrol were the most effective biopesticides in both tests. EcoRaider [Geraniol (1%), Cedar Extract (1%) and Sodium Lauryl Sulfate (2%)] caused 100 percent mortality after 10 days in both tests. Bed Bug Patrol [Clove Oil (0.003%), Peppermint Oil (1%) and Sodium Lauryl Sulfate (1.3%] caused an average of 92 percent and 91 percent mortality after 10 days in the first and second experiment, respectively. Neither of these two products caused more than 75 percent mortality at three days after treatment…Bed Bug Bully [Mint Oil (0.25%), Clove Oil (0.3%), Citronella Oil (0.4%) and Rosemary Oil (0.4%)] caused 60 percent mortality after 10 days.”

Thus, the need for a patience and a multi-faceted, integrative approach to bed bug control using herbal or synthetic pesticides, tiny leaf hair-like spikes, CO2, traps, heat, cold, steam, mattress encasements, vacuuming, pheromones, clutter reduction, diatomaceous earth, silica gels, etc. If winning the war against bed bugs were easy, the insects would have been extinct long ago and you would not be reading this.

Rest assured, a CowVac is not a veterinary vaccine of some sort that magically provides insect control or renders cows autistic. Rather, it is about producing organic milk and organic milk products like butter and yogurt. A CowVac is a suction or vacuum device incorporated into a larger trapping apparatus that removes blood-sucking flies that can be an even worse livestock plague than mosquitoes or ticks. Besides being bad economics (too expensive), pesticides repeatedly applied at ever higher doses quickly select for pesticide-resistant biting flies; i.e the flies become immune. Which is not to say that insects will not develop some ingenious solution, like holding on tighter, to avoid being sucked up by strong suction. But at least development of stronger suction devices and better ways to knock insects off animals would not add pesticide residues to the environment, food chain and human diets. A human equivalent, awaiting invention, would be an enclosure of some sort designed to knockoff and suck up (vacuum off) bed bugs before they bite (see previous blog, on bed bug desperation time innovative research).

“Seven years in the making: The Cow-Vac removes horn flies from dairy cattle” was the title of a special display at a members symposium “Honoring the Career and Contributions of Veterinary Entomologist Donald A. Rutz” at the Entomological Society of America (ESA) annual meeting in the beer brewing capital of the world, Portland, Oregon. On its web site, the Center for Environmental Farming Systems (CEFS) at North Carolina State University (NCSU) in Raleigh reports: “This innovative solution is now part of routine cattle management at the CEFS Dairy Unit and has allowed the herd to be insecticide-free for 5 years.” In other words, this “alternative fly management system” designed by Steve Denning and D. Wes Watson demonstrated “the feasibility of producing organic milk.”

“The trap removed between 1.3 and 2.5 million flies annually from the research station cattle,” Denning and Watson reported to the ESA in Portland. “Prior to the installation of the trap in 2007, the cattle routinely had horn fly populations above 1000 flies per animal and would require insecticide applications for horn fly control. With a vacuum trap in place, dairy cattle at CEFS have not required or have been treated with an insecticide.” With each of the thousand horn flies sucking blood 10-12 times per day, the blood loss and associated problems were huge (USA estimated losses are over $2.26 billion per year), and organic animal agriculture was considered questionable.

“The first walk-through pasture fly trap consisted of a covered structure designed to brush flies from the animals as they passed through, with the fleeing flies captured in the screened hollow walls,” reported Denning and Watson at the ESA meeting in Portland. “Modifications to the Bruce trap have been introduced over the years. These modified traps employ the same basic mode of action; curtains to dislodge flies and light, either natural or fluorescent, to attract flies to a cage, or bug zapper. In addition to curtains, the CowVac uses air pressure to dislodge flies, and vacuum to capture flies, trapping them in a chamber until death.” So far, the Animal Rights movement has yet to recognize a right to food (animal blood, in this case) for biting flies (also animals); and the flies die a natural death from lack of animal blood as a food source. Cruelty to animals (flies), perhaps; and fodder for an ethics debate. But if you want organic milk, butter, meat, yogurt, etc…

There are YouTube videos on the vacuum trap, and the Northeast Organic Dairy Producers Alliance has an in-depth article on the CowVac and its development by fly biocontrol specialist Tom Spalding of Spalding Labs: “…the Horn Fly is very tough to control. It’s resistant to most every chemical control. It only reproduces in cow pastures, which means there is always productive breeding material available as no one cleans up pasture pats…For the past 16 years, North Carolina State University entomologists, Dr. Wes Watson and Steve Denning, have been researching IPM practices for pest fly control for commercial livestock and poultry operations…They have seen it all, testing at least 100’s of products…repellent on most and only a few animals with pesticide, to using electric traps, light traps, walk thru traps, feed thru products, ear tags, oilers, you name it…in 2006 as Steve was watching flies get scrapped off cows going thru a walk in trap, and then following the cow out the exit and getting right back on, he had an AH HA moment of “let’s see if we could vacuum up those little buggers”…Organic Valley heard about this unit and they sponsored a test, placing 6 units on North Carolina dairies in 2012…we made a trip to Raleigh, NC to see it. I knew from our efforts using Fly Predators to control Horn Flies that this little insect was a big deal. It took a lot of work as you had to put the Fly Predators in the pastures where the cows has just been and that only worked for those doing intensive grazing. Harrowing or running a screen drag over the pastures made a big difference too, but all those things took more time than most dairymen had. If this vac thing worked it would solve a horrible problem every grazier has…We agreed to license the technology from NC State and so began the redesign for production and optimization. This is the second unlikely alignment of the stars. I run a beneficial insect company, but I’m a mechanical engineer (ME) by schooling and in the 30 years prior had started a number of high tech companies…we refined the airflow on real animals. While the simulated cow got us very close to optimized performance, we actually were blowing too much air…”

KIDNEY BEAN LEAF hairs, an ancient Balkan folk remedy to ameliorate bed bugs biting like vampires in the nighttime and wee morning hours, are in essence medieval warfare pikes barbarically impaling bed bugs resistant to 20th and 21st century synthetic pesticides. The resurrection of kidney bean leaves from Balkan folklore is a measure of human desperation, and an example of an IPM (Integrated Pest Management) strategy combining multiple weapons and tactics to fight this modern-day plague. According to The Journal of the Royal Society Interface, a modern offshoot of the one of the earliest medieval gatherings (mid-1600s) of natural philosophers, scientists and scientific craftsmen (instrument makers) into an official organization, those Balkan peasants knew a thing or two about fighting pestilence with “primitive” botanical remedies. Ultimately, bed bug-impaling bean hair “swords” or fabricated replicas will be combined in IPM strategies with other tactics, including ancient Ayurvedic Asian herbal remedies like neem tree oils (see previous blog).

You are not alone in being plagued by bed bugs: According to the journal Medical and Veterinary Entomology (Davies et al., 2012) there are “over 4 millennia of recorded narratives dating back to medieval European texts, classical Greek writings and the Jewish Talmud” and “archaeologists excavating a 3550-year-old workmen’s village at el-Amarna in Egypt found fossilized bed bug remains.” Plus bed bug “Females lay one or two eggs every day, and each female may lay 200–500 eggs in her lifetime, which may be 6 months or longer.” Modern heated buildings with lots of cracks, crevices and hiding places are even more comfortable for bed bugs than the ancient unheated buildings and caves of our ancestors.

The search for botanical remedies is perhaps equally ancient. Sir Francis Avery Jones, writing in the Journal Of The Royal Society Of Medicine (v. 89, Dec. 1996): “In the Stone Age the hunter-gatherers have learnt by hard experience…Over the eons they could have recognized plants which dulled pain, induced sleep, healed wounds, or poisoned animals or their enemies like wolfsbane…In Iraq there is a well-preserved grave of Neanderthal man, dated to some 60,000 years ago, with grains of flower pollen thickly scattered around the bones. The pollen came from eight different species still grown in Iraq today, some having recognized medicinal uses…Very early documents from China, Egypt, Sumaria and India describe the uses of anise, mustard, caraway, mint, saffron, thyme, cardamom, turmeric, cloves and pepper. The herbals reached their peak in the first century AD when the Greek physician Dioscorides assembled his vast De Materia Medica, recording the name, description, habit and medical use of some 600 plants.”

Bean leaves in comparison are a relatively modern bed bug botanical, a variant on the Tudor England practice of covering floors with pest-repellent (e.g. versus fleas, flies, plague, gaol fever/typhus) strewing herbs for their uplifting aromatic properties (e.g. rosemary, woodruff, various mints, box, lavender, santolina, hyssop, balm, cleavers, costmary, marjoram, meadowsweet, tansy). Queen Elizabeth’s use of meadowsweet leaves and flowers was described in The Herbal or Generall Historie of Plantes (1597) by John Gerard: “leaves and floures of meadowsweet farre excell all other strewing herbs for to deck up houses, for the smell makes the heart merrie and joyful and delights the senses.”

The Balkan remedy of bed bugs becoming entangled in hooked bean leaf hairs was written about by someone named Bogdandy in 1927 in the journal Naturwissenschaften and then again in 1943 by the USDA’s Henry Richardson in the Journal of Economic Entomology. According to a 2013 issue of The Journal of the Royal Society Interface, whose authors included Catherine Loudon of the University of California Irvine, who talked about the subject at the Entomological Society of America (ESA): “Historical reports describe the trapping of bed bugs in Balkan countries by leaves from bean plants strewn on the floor next to beds. During the night, bed bugs walking on the floor would accumulate on these bean leaves, which were collected and burned the following morning to exterminate the bed bugs.”

Fire, burning bean leaves that have “hooked” or “trapped” bed bugs, might be considered an extreme and specialized form of pest control heat treatment to be practiced with extreme caution. But compared to combating blood-sucking (vampirism) and werewolfism (Lycanthropy) in Hollywood B-movies, who’s to say. YouTube has videos showing bed bugs getting snagged by bean leaf hairs, and a simulation indicating that real bean leaves are still better than synthetic fabrics fabricated to mimick bean leaves. Kidney bean varieties are best for impaling passing bed bugs, and easy to use around a bed. But some lima bean varieties and small passion flower leaves also work, said Loudon. Interestingly, like computer chips, bean hairs that snag bed bugs best are toughened with silicon, unlike synthetic fabric hairs so far fabricated from substances like dental molding.

But given enough time, I would expect researchers in some dark Transylvanian lab in the Vampire District or in some light-splashed lab with surfboards along Frankenstein Row on the southern California coast to focus their scanning electron microscopes under high and low vacuums and eventually patent and reveal to the world nano-fabric silica hairs of a monstrous nature (to bed bugs) that can protectively surround sleepers and trap bed bugs before they bite. Or perhaps the genetic engineers will get there first with a carnivorous plant (the Venus Bed Bug Trap) for biocontrol. But if you’re keeping score, for most of human history, with some periods of remission, Team Bed Bug is still on top. In the meantime, pleasant dreams; and don’t let the bed bugs bite.

THE NEEM TREE (Azadirachta indica), a medicinal mahogany tree (Meliaceae) native to arid broadleaf and scrub forests in Asia (e.g. India), has been used for over 4,000 years in Vedic medicine and has a heavy, durable wood useful for furniture and buildings because it is resistant to termites and fungi. Nonetheless, despite US EPA registration as a pesticide for crop and home use and a long legacy of neem seed oil use for cosmetics, shampoos, toothpastes and medicines in India, Ohio State University researcher Susan Jones could not find any households near her Columbus, Ohio, home willing to try neem in her bed bug control experiments.

“We had no study takers because of the regulatory requirements,” which scared off people, Jones told the Entomological Society of America (ESA) Annual Meeting. “You have to read page after page to residents about toxicity without being able to talk about the toxicity of alternative products” not as safe as neem. In October 2012, an empty house with bed bugs became available for research when its occupant opted to escape a bad bed bug infestation by leaving the infested home; and inadvertently transferred the infestation to their new home.

Jones monitored the empty house by placing in each room four (4) Verifi(TM) CO2 (carbon dioxide) traps and four (4) Climbup(R) Interceptor traps. Visual inspections revealed few bed bugs. On October 24, 2012, prior to neem treatments, 38 bed bugs were captured in Climbup(R) traps, indicating bed bug infestations only in the master bedroom and bed of the empty house. Eight Verifi(TM) traps captured 48 bed bugs in the dining room, guest room and master bedroom. As part of an IPM (integrated pest management) approach using multiple treatment tools: Electrical sockets were treated with MotherEarth(R) D diatomaceous earth; 3.67 gal (13.9 l) at a rate of 1 gal/250 ft2 (3.9 l/23 m2). Gorilla Tape(R) was used to seal around the doors and exclude bed bug movement from other rooms.

The neem seed oil product, Cirkil(TM) RTU, was sprayed in various places, including on books, backs of picture frames and cardboard boxes. Vials of the insecticide-susceptible Harlan bed bug strain were placed around the house for on-site neem seed oil vapor toxicity assays. Two days after spraying, bed bug mortality from neem seed oil vapors was highest in confined spaces; with 48% mortality in vials placed between the mattress and box spring, versus 28% mortality in open spaces. On Nov. 6, two weeks post-treatment, 123 dead bed bugs were vacuumed up and live bed bugs were detected in a second bedroom. Bed bug numbers were low because the monitoring traps were doing double duty, also providing population suppression by removing many bed bugs.

Herbal oils can also be combined with heat chambers at 50 C (122 F) or carbon dioxide (CO2) fumigation chambers to combat bed bugs. However, heat chambers are expensive, and CO2 fumigation with dry ice can pose handling difficulties and room air circulation issues, Dong-Hwan Choe of the University of California, Riverside, told the Entomological Society of America (ESA).

Herbal essential oils are useful against head lice, and in Choe’s native Korea clove oil from from the leaves and flower buds of clove plants (Syzygium aromaticum) is used in aromatherapy and as a medicine. Clove oil is rich in GRAS (Generally Recognized as Safe) compounds such as eugenol, beta-caryophyllene and methyl salicylate (sometimes called wintergreen oil), which are useful as vapors in control of insects and microbes. In dentistry, clove oil (eugenol) is widely used as an antiseptic and pain reliever.

Temprid(TM) SC and Demand(R) CS proved best on the cotton fabric test. In arena bioassays with Climbup(R)Interceptor traps, none of the four insecticides were repellent to bed bugs (i.e. repellency was less than 30%). Ecoraider(TM) was equal to Temprid(TM) SC and Demand(R) CS against the tough to kill bed bug eggs. Singh concluded that field tests of Ecoraider(TM) as a biopesticide were warranted.

Changlu Wang of Rutgers told the ESA that travelers might be protected from bed bug bites and bring home fewer bed bugs if protected by essential oil repellents, as well as by more traditional mosquito and tick repellents like DEET, permethrin and picaridin. Repellents are more convenient and less expensive than non-chemical alternatives such as sleeping under bed bug tents and bandaging yourself in a protective suit.

Isolongifolenone, an odorless sesquiterpene found in the South American Tauroniro tree (Humiria balsamifera), is among the botanicals being studied, as it can also be synthesized from turpentine oil and is as effective as DEET against mosquito and tick species. Bed bug arena tests involve putting a band of repellent around a table leg, with a Climbup(R)Interceptor trap below. If the bed bug falls into the trap, it is deemed to have been repelled from the surface above. In actual practice, the bed bug climbs up the surface and goes horizontal onto the treated surface and drops or falls off if the surface is repellent. Isolongifolenone starts losing its repellency after 3 hours; 5%-10% DEET works for about 9 hours. In arena tests with host cues, 25% DEET keeps surfaces repellent to bed bugs for 2 weeks. But isolongifolenone is considered safer, and Wang is testing higher rates in hopes of gettting a full day’s protection.

CARBON DIOXIDE GAS, an essential nutrient for photosynthesis and the human and animal food chain consuming green plants, can also play a key role in bed bug control. As an attractant, carbon dioxide (CO2) is useful for monitoring and trapping bed bugs and other vampire-like blood-suckers attracted to the gas, including ticks, mosquitoes, and assorted biting flies. Carbon dioxide gas, which has been used to fumigate everything from stored grain and food products to freight containers, museum collections, and hotel and motel rooms, can also be used to fumigate clothing, furnishings, books, electronics, and other bed bug-infested items.

Carbon, carbon dioxide, and the carbon cycle are integral to our very existence on planet Earth. “The carbon of the Earth comes in several forms,” writes University of Cambridge chemist John Emsley in his fascinating Oxford University Press book, Nature’s Building Blocks (An A-Z Guide to the Elements). “Most of what we eat –carbohydrates, fats, proteins and fibre – is made up of compounds of carbon…most ingested carbon compounds are oxidized to release the energy they contain, and then we breathe out the carbon as carbon dioxide. This joins the other carbon dioxide in the atmosphere, from where it will again be extracted by plants and become part of the carbon cycle of nature…The cycle rules the tempo of life on Earth and turns over 200 billion tonnes of carbon each year…In this way carbon is passed up the various food chains, with each recipient releasing some as carbon dioxide, until most carbon is back where it started.”

Does this mean that using carbon dioxide for bed bug control is environmentally acceptable, since it is kind of a “miracle of life” gas behind photosynthesis and plant life? Or is carbon dioxide really more the evil greenhouse or global-warming gas causing global climatic havoc and deserving of punishment via carbon taxes and elimination from the atmosphere via geological carbon sequestration (storage) schemes? Perhaps we should offset carbon dioxide releases for bed bug pest control with offsetting carbon dioxide injections into greenhouses, where elevated CO2 levels increase yields of greenhouse roses, tomatoes, cucumbers, peppers and other crops.

“Carbon is probably the most important element from an environmental point of view,” writes Emsley in Nature’s Building Blocks. “The Earth’s early atmosphere may have contained a lot of carbon dioxide and methane, but once life evolved that began to change. Today, there is very little of these gases and a lot of oxygen instead, thanks chiefly to the action of plants which convert carbon dioxide and water into carbohydrate and oxygen by photosynthesis. The Earth’s atmosphere contains an ever-increasing concentration of carbon dioxide and carbon monoxide, from fossil fuel burning, and of methane, from paddy fields and cows. Human contributions to these sources are still minor compared with natural sources: most carbon dioxide comes from plants, microbes and animals, while methane is given off by swamps, marshes and termite mounds.”

Obviously best to avoid bed bug infestations, and not have to think about remedies like carbon dioxide trapping or fumigations. Italian chemist Primo Levi makes the most persuasive literary argument: “Carbon dioxide, that is, the aerial form of carbon…this gas which constitutes the raw material of life, the permanent store upon which all that grows draws, and the ultimate destiny of all flesh, is not one of the principal components of air but rather a ridiculous remnant, an ‘impurity,’ thirty times less abundant than argon, which nobody even notices. The air contains 0.03 percent; if Italy was air, the only Italians fit to build life would be, for example, the 15,000 inhabitants of Milazzo in the province of Messina. This, on the human scale, is ironic acrobatics, a juggler’s trick, an incomprehensible display of omnipotence-arrogance, since from this ever renewed impurity of the air we come, we animals and we plants, and we the human species, with our four billion discordant opinions, our millenniums of history…”

Bed bugs concern themselves little with environmental correctness, and just tune into characteristics like the heat and carbon dioxide released by metabolizing warm-blooded meal hosts like humans, poultry, rodents, rabbits, etc. A flush from a CO2 cartridge is enough to flush bed bugs from their harborages or hiding places onto a bed in search of a meal. But more naturally, bed bugs follow CO2 gradients to locate live hosts for their blood meals.

“Carbon dioxide has been shown by several researchers to be the most effective attractant for bed bugs,” University of Florida-Gainesville entomologist Philip Koehler told a recent Entomological Society of America (ESA) annual meeting. Humans produce about 700 mg (0.02 oz) of CO2 per minute. “Thus, detectors with very slow CO2 releases cannot compete with human hosts,” said Koehler. “A rapid CO2 release is a better mimic to the human breathing pattern. Detectors with fast CO2 release captured about 4x more bed bugs than detectors with slow release.”

Trapping or monitoring bed bugs with CO2 is complicated by the fact that at different times in the life cycle bed bugs seek out hosts (releasing CO2) for blood meals when hungry; and then when well-fed, instead of CO2 bed bugs seek shelter in groups or cracks and crevices. So although CO2 is the better lure for hungry bed bugs, bed bugs that have fed have different needs and respond to different lures.

A commercial product, FMC’s Verifi(TM) trap, is a dual-action detector combining “fast CO2 generation with liquid kairomone and pheromone lures to attract both host-seeking bed bugs and aggregation-seeking bed bugs,” Koehler told the ESA. Carbon dioxide and the kairomone lure blood-seeking bed bugs into a pitfall part of the trap from which there is no escape. A pheromone lures harborage- or aggregation-seeking bed bugs seeking shelter in cracks and crevices into another part of the trap.

“An inexpensive detector that can be left in place and routinely serviced is needed to aid pest management professionals,” Ohio State University’s Susan Jones told the ESA. “Rutger’s do-it-yourself dry ice (frozen CO2) traps are a cheap and effective method for overnight surveys of potentially infested habitations.” An experiment in a 13-story high-rise apartment building in Columbus, Ohio compared (see You Tube video) 3 Verifi(TM) bed bug detectors per room with 1 CO2-generating dry ice trap per room and canine (dog) detection teams (2 dogs/room; same handler).

Verifi(TM) traps detected bed bugs in 11 of 17 infested rooms in the first 24 hours; and in 14 of 17 infested rooms within a week. Dry ice traps had similar efficacy. Dogs detected bed bugs in 19 rooms, including 3 rooms where neither visual inspections nor dry ice or Verifi(TM) traps detected anything. But the dogs were also not perfect, as each dog also missed 1 room rated positive for bed bugs. So the quest to capture bed bugs with carbon dioxide and other lures goes on.

Human ingenuity seems almost unlimited when it comes to traps. Carbon dioxide, heat and other attractants are all being tested with traps as varied as Susan McKnight Inc.’s Climbup bed bug trap and pitfall traps made from inverted dog bowls painted black on the outside. Rutgers’ Narinderpal Singh tested CO2, heat, and lures such as nonanol, octanol, 1-octen-3-ol, coriander, and spearmint with inverted dog bowl pitfall traps. CO2 had an additive effect with multiple-component lures in inverted dog bowl traps, and may be developed into an inexpensive monitoring system for detecting low levels of bed bugs. Trials with baited traps are continuing.

Both carbon dioxide and ozone show fumigant potential against bed bugs. Purdue University’s Kurt Saltzmann told the ESA of “Two devices capable of delivering ozone to laboratory fumigation chambers.” One device delivered a short exposure to high ozone levels, and the other long exposure to low ozone levels. “Preliminary experiments showed that adult male bed bugs were susceptible to relatively short periods of ozone exposure when high concentrations of ozone were used,” said Saltzmann. “100% mortality was achieved when bed bugs were exposed to 1800 ppm ozone for 150 minutes.” Low ozone fumigation is also being tested with 1-2% hydrogen peroxide for up to 72 hours.

Carbon dioxide (CO2) is used by libraries, museums, and others as an insect-killing fumigant. Indeed, dry ice (frozen CO2) to release CO2 gas is cheaper than washing and drying fabrics to kill bed bugs, Rutgers University’s Changlu Wang told the ESA. At an 80% concentration, CO2 kills all bed bug eggs in 24 hours (eggs are the toughest bed bug life stage to kill). A 50% CO2 concentration for 8 hours is sufficient to kill bed bug nymphs (immatures) and adults.

Wang’s CO2 fumigations involved filling Husky garbage bags 90% full of items such as mattress covers and fabrics, leaving little room for air. Then the bags were sealed with dry ice inside for several hours. Books, electronics, toys and other items damaged by heat treatments might benefit from the low temperatures created by dry ice treatments. However, for safety reasons Wang recommends wearing gloves and turning on fans for ventilation when opening many bags filled with carbon dioxide gas (fumigant).